1. Field of the Invention
Improved Geothermal Well Head Assembly.
2. Description of the Prior Art
In recent years, due to the uncertainty of petroleum and natural gas as a source of energy, the production of power from geothermal wells has taken on increased importance. A troublesome problem in the production of geothermal energy, is maintaining a seal at the well head between the ambient atmosphere and the interior of the valve manifold through which the heated fluid from the geothermal zone flows.
The difficulty in so maintaining the seal is due to the substantial longitudinal and expansion and contraction that takes place in the casing or tubing string through which heated fluid flows relative to the stationary well head assembly. In the past it has been common practice to employ multiple groups of resilient rings to effect the seal to allow for such expansion and contraction, with the groups of rings having the same force exerted thereon to radially expand the same. Such a mode of sealing has been found unsatisfactory in that there is no correlation between the forces exerted on the two groups of resilient rings, and as a result an excessive force may be exerted on one group and an insufficient force on the other group. A major object of the present invention is to furnish a geothermal well head assembly that allows longitudinal expansion and contraction of the string of casing that extend to the producing zone relative to the surface string of casing by the use of compressed first and second resilient seals, and the seals having first and second manually operated means operatively associated therewith that may be periodically used to independently adjust the compression on the seals without shutting down the well.
The shutting down of a geothermal well by pumping heavy mud downwardly in the bore hole thereof is highly undesirable as the future productivity of the well may be impaired, and in some instances ruined.